The Washington DC Regional Pediatric AIDS Clinical Research Unit (PACTU) will function as a member of the Pediatric AIDS Treatment Group (PACTG) with the Coordinating and Operations Center (CORC) --Spector. The Goals and Specific Aims of the PACTU are the same as those identified in the Scientific Agenda of the PACTG--CORC and in the RFA. The three primary goals are (1) to decrease mother-to-infant transmission of HIV to less than 2%; (2) to achieve a 90% 10 year survival for children perinatally infected with HIV and (3) to develop novel strategies for early treatment Of newly infected infants and adolescents. The PACTU will conduct Phase I, II and Ill clinical studies with the PACTG. The PACTU has available a significant number of HIV infected patients for possible study. Each year there are 50 new pregnant women, 40 new children and 20 new adolescents and young adults. The PACTU also follows 245 children and 85 adolescents and young adults who are potential candidates for studies.. The PACTU has four years of experience with Phase I, II and II, ACTG studies involving perinatal transmission, primary therapy, opportunistic infections, immune based therapy and long-term follow-up. Accrual has always been above target and the quality of data has been excellent. The PACTU is particularly active in studies to reduce perinatal transmission and has submitted concept sheets and capsules to the ACTG and has conducted supplemental investigations in this area of research. Members of the PACTU serve in leadership positions of the PACTG. The PACTU supports the Scientific Agenda of the CORC by participating in developing, monitoring and revising the Scientific Agenda; serving in leadership positions on the RACs and Committees; submitting capsules and concept sheets for clinical and more fundamental studies; conducting the research protocols of the RACs and Committees; serving on protocol teams; conducting supplemental investigations; and participating in the reporting of results through meetings and scientific publications.